Thread: << complete newb :)

Im just wondering, whats the difference between

std::cout

and cout

I've seen both in some sources, but I don't understand them. And what does :: do? : ) thanks

:: is the scope resolution operator.

std::cout means to use the cout that resides in the std namespace
cout means to use the cout in whatever namespace you are in

ok then, keep in mind that im completely new to c++, i program vb but this is way different

whats a namespace ?

Instead of prefixing every function call with std::, you could put "using namespace std" after the includes. I think I read about a disadvantage to that somewhere, but I cant remember what.

What is a namespace?

The disadvantage is that nothing in the global namespace (or another imported namespace) can then have the same name as anything you have included in whatever namespaces that you have done away with by using the 'using' keyword.

Safer, is to say 'using std::cout;', 'using std::endl;', etc for only the identifiers you need. Safer still, is to stick with just using the namespace identifier for scope resolution when you use the identifiers.

thats how i see it:

imagine you develop a class library, and share it with your costumers etc, so they can use your library.
imagine you make a class that is part of your library called Cars, ie:
class Cars{
//code here
};

i install your library in my computer, but you'r not so lucky because other guy made another class that i have installed in my pc and he calle it Cars too, ok if pretend to use that class it will not do what i want because i both clases collide.

how can you prevent this? when u develop a set of classes is a good programming to put it
into namespaces ie

namespace terra
{
//here i put all my code and clases ie
class Cars{
//code here
};
}

ok know when u share your library your users to make use of the Cars class they must use
terra::Cars
or intead of typing everytime terra::something you define the namespace ie:
using namespace terra;
know you dont need to type terra::

then the user can start to create objects with that class with no problems
ie. Cars toyota;

if you r more lost after reading my post avoid it, because my english sucks

This is also similar to my question about what \n does. What's the difference between no \n and \n. What does \n do?

\n is the newline character. As the name suggests it causes a newline to be outputted

Also, I think writing a '\n' to a file opened in text mode will actually output a "\r\n" unless you open the file in binary mode

Not if you open it in a linux enviroment.

Well, newline is just a character, and it's interpretation is application-specific (or so I imagine). If you so wished, you could make a text editor or console which treated £ as a newline character instead.